Use of SQL Server cursors

DECLARE @Id NVARCHAR(MAX) DECLARE @UserName NVARCHAR(MAX)  DECLARE @Password NVARCHAR(MAX) DECLARE @NickName NVARCHAR(MAX)  Create Table#tmp (IdNVARCHAR(MAX), UserNameNVARCHAR(MAX), PasswordNVARCHAR(MAX), nicknameNVARCHAR(MAX))--Create a temporary data table--declares that the number of parameters in a cursor Mycursor,select statement must be the same as the variable name taken from the cursorDECLAREMyCursorCURSOR   for      SELECTId,username,password,nickname fromdbo. UsersOPENMyCursor--Open Cursor--extract the data from Grandperi to the variable we just declared (moving the cursor to the first data, extracting the first piece of data in the variable)FETCH NEXT  fromMyCursor into @Id,@UserName,@Password,@NickName        --determining the state of a cursor--0 FETCH statement succeeded---1 Fetch statement failed or row not in result set---2 rows that were fetched do not exist while(@ @fetch_status = 0)--if the last operation succeeds, the loop continues    BEGIN                --shows the value we take out each time we use a cursor.        --Print (@Id + '--------' [email protected]+ '--------' [email protected]+ '----' [email protected]        --Conditional Judgment        if(@Id>=Ten)        begin            INSERT  into#tmp (Id,username,password,nickname)VALUES(@Id,@UserName,@Password,@NickName)         End        --use a cursor to remove a record (continue to remove a row of data)        FETCH NEXT  fromMyCursor into @Id,@UserName,@Password,@NickName       END  CLOSEMyCursor--Close CursorsdeallocateMyCursor--undoing cursors (freeing resources)SELECT *  from#tmp;--Querying temporary tablesDROP TABLE#tmp--Delete temporary table 

Use of SQL Server cursors